crypto: bfin_crc - CRC hardware driver for BF60x family processors.

The CRC peripheral is a hardware block used to compute the CRC of the block
of data. This is based on a CRC32 engine which computes the CRC value of 32b
data words presented to it. For data words of < 32b in size, this driver
pack 0 automatically into 32b data units. This driver implements the async
hash crypto framework API.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 789 insertions, 1 deletions

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 1092a770482..dd4d5af6c31 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -325,4 +325,11 @@ if CRYPTO_DEV_UX500
 	source "drivers/crypto/ux500/Kconfig"
 endif # if CRYPTO_DEV_UX500
 
+config CRYPTO_DEV_BFIN_CRC
+	tristate "Support for Blackfin CRC hardware"
+	depends on BF60x
+	help
+	  Newer Blackfin processors have CRC hardware. Select this if you
+	  want to use the Blackfin CRC module.
+
 endif # CRYPTO_HW
diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
index 01390325d72..d5062bb7a1f 100644
--- a/drivers/crypto/Makefile
+++ b/drivers/crypto/Makefile
@@ -14,4 +14,5 @@ obj-$(CONFIG_CRYPTO_DEV_OMAP_AES) += omap-aes.o
 obj-$(CONFIG_CRYPTO_DEV_PICOXCELL) += picoxcell_crypto.o
 obj-$(CONFIG_CRYPTO_DEV_S5P) += s5p-sss.o
 obj-$(CONFIG_CRYPTO_DEV_TEGRA_AES) += tegra-aes.o
-obj-$(CONFIG_CRYPTO_DEV_UX500) += ux500/
\ No newline at end of file
+obj-$(CONFIG_CRYPTO_DEV_UX500) += ux500/
+obj-$(CONFIG_CRYPTO_DEV_BFIN_CRC) += bfin_crc.o
diff --git a/drivers/crypto/bfin_crc.c b/drivers/crypto/bfin_crc.c
new file mode 100644
index 00000000000..5398580b431
--- /dev/null
+++ b/drivers/crypto/bfin_crc.c
@@ -0,0 +1,780 @@
+/*
+ * Cryptographic API.
+ *
+ * Support Blackfin CRC HW acceleration.
+ *
+ * Copyright 2012 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/unaligned/access_ok.h>
+#include <linux/crypto.h>
+#include <linux/cryptohash.h>
+#include <crypto/scatterwalk.h>
+#include <crypto/algapi.h>
+#include <crypto/hash.h>
+#include <crypto/internal/hash.h>
+
+#include <asm/blackfin.h>
+#include <asm/bfin_crc.h>
+#include <asm/dma.h>
+#include <asm/portmux.h>
+
+#define CRC_CCRYPTO_QUEUE_LENGTH	5
+
+#define DRIVER_NAME "bfin-hmac-crc"
+#define CHKSUM_DIGEST_SIZE      4
+#define CHKSUM_BLOCK_SIZE       1
+
+#define CRC_MAX_DMA_DESC	100
+
+#define CRC_CRYPTO_STATE_UPDATE		1
+#define CRC_CRYPTO_STATE_FINALUPDATE	2
+#define CRC_CRYPTO_STATE_FINISH		3
+
+struct bfin_crypto_crc {
+	struct list_head	list;
+	struct device		*dev;
+	spinlock_t		lock;
+
+	int			irq;
+	int			dma_ch;
+	u32			poly;
+	volatile struct crc_register *regs;
+
+	struct ahash_request	*req; /* current request in operation */
+	struct dma_desc_array	*sg_cpu; /* virt addr of sg dma descriptors */
+	dma_addr_t		sg_dma; /* phy addr of sg dma descriptors */
+	u8			*sg_mid_buf;
+
+	struct tasklet_struct	done_task;
+	struct crypto_queue	queue; /* waiting requests */
+
+	u8			busy:1; /* crc device in operation flag */
+};
+
+static struct bfin_crypto_crc_list {
+	struct list_head	dev_list;
+	spinlock_t		lock;
+} crc_list;
+
+struct bfin_crypto_crc_reqctx {
+	struct bfin_crypto_crc	*crc;
+
+	unsigned int		total;	/* total request bytes */
+	size_t			sg_buflen; /* bytes for this update */
+	unsigned int		sg_nents;
+	struct scatterlist	*sg; /* sg list head for this update*/
+	struct scatterlist	bufsl[2]; /* chained sg list */
+
+	size_t			bufnext_len;
+	size_t			buflast_len;
+	u8			bufnext[CHKSUM_DIGEST_SIZE]; /* extra bytes for next udpate */
+	u8			buflast[CHKSUM_DIGEST_SIZE]; /* extra bytes from last udpate */
+
+	u8			flag;
+};
+
+struct bfin_crypto_crc_ctx {
+	struct bfin_crypto_crc	*crc;
+	u32			key;
+};
+
+
+/*
+ * derive number of elements in scatterlist
+ */
+static int sg_count(struct scatterlist *sg_list)
+{
+	struct scatterlist *sg = sg_list;
+	int sg_nents = 1;
+
+	if (sg_list == NULL)
+		return 0;
+
+	while (!sg_is_last(sg)) {
+		sg_nents++;
+		sg = scatterwalk_sg_next(sg);
+	}
+
+	return sg_nents;
+}
+
+/*
+ * get element in scatter list by given index
+ */
+static struct scatterlist *sg_get(struct scatterlist *sg_list, unsigned int nents,
+				unsigned int index)
+{
+	struct scatterlist *sg = NULL;
+	int i;
+
+	for_each_sg(sg_list, sg, nents, i)
+		if (i == index)
+			break;
+
+	return sg;
+}
+
+static int bfin_crypto_crc_init_hw(struct bfin_crypto_crc *crc, u32 key)
+{
+	crc->regs->datacntrld = 0;
+	crc->regs->control = MODE_CALC_CRC << OPMODE_OFFSET;
+	crc->regs->curresult = key;
+
+	/* setup CRC interrupts */
+	crc->regs->status = CMPERRI | DCNTEXPI;
+	crc->regs->intrenset = CMPERRI | DCNTEXPI;
+	SSYNC();
+
+	return 0;
+}
+
+static int bfin_crypto_crc_init(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct bfin_crypto_crc_ctx *crc_ctx = crypto_ahash_ctx(tfm);
+	struct bfin_crypto_crc_reqctx *ctx = ahash_request_ctx(req);
+	struct bfin_crypto_crc *crc;
+
+	dev_dbg(crc->dev, "crc_init\n");
+	spin_lock_bh(&crc_list.lock);
+	list_for_each_entry(crc, &crc_list.dev_list, list) {
+		crc_ctx->crc = crc;
+		break;
+	}
+	spin_unlock_bh(&crc_list.lock);
+
+	if (sg_count(req->src) > CRC_MAX_DMA_DESC) {
+		dev_dbg(crc->dev, "init: requested sg list is too big > %d\n",
+			CRC_MAX_DMA_DESC);
+		return -EINVAL;
+	}
+
+	ctx->crc = crc;
+	ctx->bufnext_len = 0;
+	ctx->buflast_len = 0;
+	ctx->sg_buflen = 0;
+	ctx->total = 0;
+	ctx->flag = 0;
+
+	/* init crc results */
+	put_unaligned_le32(crc_ctx->key, req->result);
+
+	dev_dbg(crc->dev, "init: digest size: %d\n",
+		crypto_ahash_digestsize(tfm));
+
+	return bfin_crypto_crc_init_hw(crc, crc_ctx->key);
+}
+
+static void bfin_crypto_crc_config_dma(struct bfin_crypto_crc *crc)
+{
+	struct scatterlist *sg;
+	struct bfin_crypto_crc_reqctx *ctx = ahash_request_ctx(crc->req);
+	int i = 0, j = 0;
+	unsigned long dma_config;
+	unsigned int dma_count;
+	unsigned int dma_addr;
+	unsigned int mid_dma_count = 0;
+	int dma_mod;
+
+	dma_map_sg(crc->dev, ctx->sg, ctx->sg_nents, DMA_TO_DEVICE);
+
+	for_each_sg(ctx->sg, sg, ctx->sg_nents, j) {
+		dma_config = DMAFLOW_ARRAY | RESTART | NDSIZE_3 | DMAEN | PSIZE_32;
+		dma_addr = sg_dma_address(sg);
+		/* deduce extra bytes in last sg */
+		if (sg_is_last(sg))
+			dma_count = sg_dma_len(sg) - ctx->bufnext_len;
+		else
+			dma_count = sg_dma_len(sg);
+
+		if (mid_dma_count) {
+			/* Append last middle dma buffer to 4 bytes with first
+			   bytes in current sg buffer. Move addr of current
+			   sg and deduce the length of current sg.
+			 */
+			memcpy(crc->sg_mid_buf +((i-1) << 2) + mid_dma_count,
+				(void *)dma_addr,
+				CHKSUM_DIGEST_SIZE - mid_dma_count);
+			dma_addr += CHKSUM_DIGEST_SIZE - mid_dma_count;
+			dma_count -= CHKSUM_DIGEST_SIZE - mid_dma_count;
+		}
+		/* chop current sg dma len to multiple of 32 bits */
+		mid_dma_count = dma_count % 4;
+		dma_count &= ~0x3;
+
+		if (dma_addr % 4 == 0) {
+			dma_config |= WDSIZE_32;
+			dma_count >>= 2;
+			dma_mod = 4;
+		} else if (dma_addr % 2 == 0) {
+			dma_config |= WDSIZE_16;
+			dma_count >>= 1;
+			dma_mod = 2;
+		} else {
+			dma_config |= WDSIZE_8;
+			dma_mod = 1;
+		}
+
+		crc->sg_cpu[i].start_addr = dma_addr;
+		crc->sg_cpu[i].cfg = dma_config;
+		crc->sg_cpu[i].x_count = dma_count;
+		crc->sg_cpu[i].x_modify = dma_mod;
+		dev_dbg(crc->dev, "%d: crc_dma: start_addr:0x%lx, "
+			"cfg:0x%lx, x_count:0x%lx, x_modify:0x%lx\n",
+			i, crc->sg_cpu[i].start_addr,
+			crc->sg_cpu[i].cfg, crc->sg_cpu[i].x_count,
+			crc->sg_cpu[i].x_modify);
+		i++;
+
+		if (mid_dma_count) {
+			/* copy extra bytes to next middle dma buffer */
+			dma_config = DMAFLOW_ARRAY | RESTART | NDSIZE_3 |
+				DMAEN | PSIZE_32 | WDSIZE_32;
+			memcpy(crc->sg_mid_buf + (i << 2),
+				(void *)(dma_addr + (dma_count << 2)),
+				mid_dma_count);
+			/* setup new dma descriptor for next middle dma */
+			crc->sg_cpu[i].start_addr = dma_map_single(crc->dev,
+					crc->sg_mid_buf + (i << 2),
+					CHKSUM_DIGEST_SIZE, DMA_TO_DEVICE);
+			crc->sg_cpu[i].cfg = dma_config;
+			crc->sg_cpu[i].x_count = 1;
+			crc->sg_cpu[i].x_modify = CHKSUM_DIGEST_SIZE;
+			dev_dbg(crc->dev, "%d: crc_dma: start_addr:0x%lx, "
+				"cfg:0x%lx, x_count:0x%lx, x_modify:0x%lx\n",
+				i, crc->sg_cpu[i].start_addr,
+				crc->sg_cpu[i].cfg, crc->sg_cpu[i].x_count,
+				crc->sg_cpu[i].x_modify);
+			i++;
+		}
+	}
+
+	dma_config = DMAFLOW_ARRAY | RESTART | NDSIZE_3 | DMAEN | PSIZE_32 | WDSIZE_32;
+	/* For final update req, append the buffer for next update as well*/
+	if (ctx->bufnext_len && (ctx->flag == CRC_CRYPTO_STATE_FINALUPDATE ||
+		ctx->flag == CRC_CRYPTO_STATE_FINISH)) {
+		crc->sg_cpu[i].start_addr = dma_map_single(crc->dev, ctx->bufnext,
+						CHKSUM_DIGEST_SIZE, DMA_TO_DEVICE);
+		crc->sg_cpu[i].cfg = dma_config;
+		crc->sg_cpu[i].x_count = 1;
+		crc->sg_cpu[i].x_modify = CHKSUM_DIGEST_SIZE;
+		dev_dbg(crc->dev, "%d: crc_dma: start_addr:0x%lx, "
+			"cfg:0x%lx, x_count:0x%lx, x_modify:0x%lx\n",
+			i, crc->sg_cpu[i].start_addr,
+			crc->sg_cpu[i].cfg, crc->sg_cpu[i].x_count,
+			crc->sg_cpu[i].x_modify);
+		i++;
+	}
+
+	if (i == 0)
+		return;
+
+	flush_dcache_range((unsigned int)crc->sg_cpu,
+			(unsigned int)crc->sg_cpu +
+			i * sizeof(struct dma_desc_array));
+
+	/* Set the last descriptor to stop mode */
+	crc->sg_cpu[i - 1].cfg &= ~(DMAFLOW | NDSIZE);
+	crc->sg_cpu[i - 1].cfg |= DI_EN;
+	set_dma_curr_desc_addr(crc->dma_ch, (unsigned long *)crc->sg_dma);
+	set_dma_x_count(crc->dma_ch, 0);
+	set_dma_x_modify(crc->dma_ch, 0);
+	SSYNC();
+	set_dma_config(crc->dma_ch, dma_config);
+}
+
+static int bfin_crypto_crc_handle_queue(struct bfin_crypto_crc *crc,
+				  struct ahash_request *req)
+{
+	struct crypto_async_request *async_req, *backlog;
+	struct bfin_crypto_crc_reqctx *ctx;
+	struct scatterlist *sg;
+	int ret = 0;
+	int nsg, i, j;
+	unsigned int nextlen;
+	unsigned long flags;
+
+	spin_lock_irqsave(&crc->lock, flags);
+	if (req)
+		ret = ahash_enqueue_request(&crc->queue, req);
+	if (crc->busy) {
+		spin_unlock_irqrestore(&crc->lock, flags);
+		return ret;
+	}
+	backlog = crypto_get_backlog(&crc->queue);
+	async_req = crypto_dequeue_request(&crc->queue);
+	if (async_req)
+		crc->busy = 1;
+	spin_unlock_irqrestore(&crc->lock, flags);
+
+	if (!async_req)
+		return ret;
+
+	if (backlog)
+		backlog->complete(backlog, -EINPROGRESS);
+
+	req = ahash_request_cast(async_req);
+	crc->req = req;
+	ctx = ahash_request_ctx(req);
+	ctx->sg = NULL;
+	ctx->sg_buflen = 0;
+	ctx->sg_nents = 0;
+
+	dev_dbg(crc->dev, "handling new req, flag=%u, nbytes: %d\n",
+						ctx->flag, req->nbytes);
+
+	if (ctx->flag == CRC_CRYPTO_STATE_FINISH) {
+		if (ctx->bufnext_len == 0) {
+			crc->busy = 0;
+			return 0;
+		}
+
+		/* Pack last crc update buffer to 32bit */
+		memset(ctx->bufnext + ctx->bufnext_len, 0,
+				CHKSUM_DIGEST_SIZE - ctx->bufnext_len);
+	} else {
+		/* Pack small data which is less than 32bit to buffer for next update. */
+		if (ctx->bufnext_len + req->nbytes < CHKSUM_DIGEST_SIZE) {
+			memcpy(ctx->bufnext + ctx->bufnext_len,
+				sg_virt(req->src), req->nbytes);
+			ctx->bufnext_len += req->nbytes;
+			if (ctx->flag == CRC_CRYPTO_STATE_FINALUPDATE &&
+				ctx->bufnext_len) {
+				goto finish_update;
+			} else {
+				crc->busy = 0;
+				return 0;
+			}
+		}
+
+		if (ctx->bufnext_len) {
+			/* Chain in extra bytes of last update */
+			ctx->buflast_len = ctx->bufnext_len;
+			memcpy(ctx->buflast, ctx->bufnext, ctx->buflast_len);
+
+			nsg = ctx->sg_buflen ? 2 : 1;
+			sg_init_table(ctx->bufsl, nsg);
+			sg_set_buf(ctx->bufsl, ctx->buflast, ctx->buflast_len);
+			if (nsg > 1)
+				scatterwalk_sg_chain(ctx->bufsl, nsg,
+						req->src);
+			ctx->sg = ctx->bufsl;
+		} else
+			ctx->sg = req->src;
+
+		/* Chop crc buffer size to multiple of 32 bit */
+		nsg = ctx->sg_nents = sg_count(ctx->sg);
+		ctx->sg_buflen = ctx->buflast_len + req->nbytes;
+		ctx->bufnext_len = ctx->sg_buflen % 4;
+		ctx->sg_buflen &= ~0x3;
+
+		if (ctx->bufnext_len) {
+			/* copy extra bytes to buffer for next update */
+			memset(ctx->bufnext, 0, CHKSUM_DIGEST_SIZE);
+			nextlen = ctx->bufnext_len;
+			for (i = nsg - 1; i >= 0; i--) {
+				sg = sg_get(ctx->sg, nsg, i);
+				j = min(nextlen, sg_dma_len(sg));
+				memcpy(ctx->bufnext + nextlen - j,
+					sg_virt(sg) + sg_dma_len(sg) - j, j);
+				if (j == sg_dma_len(sg))
+					ctx->sg_nents--;
+				nextlen -= j;
+				if (nextlen == 0)
+					break;
+			}
+		}
+	}
+
+finish_update:
+	if (ctx->bufnext_len && (ctx->flag == CRC_CRYPTO_STATE_FINALUPDATE ||
+		ctx->flag == CRC_CRYPTO_STATE_FINISH))
+		ctx->sg_buflen += CHKSUM_DIGEST_SIZE;
+
+	/* set CRC data count before start DMA */
+	crc->regs->datacnt = ctx->sg_buflen >> 2;
+
+	/* setup and enable CRC DMA */
+	bfin_crypto_crc_config_dma(crc);
+
+	/* finally kick off CRC operation */
+	crc->regs->control |= BLKEN;
+	SSYNC();
+
+	return -EINPROGRESS;
+}
+
+static int bfin_crypto_crc_update(struct ahash_request *req)
+{
+	struct bfin_crypto_crc_reqctx *ctx = ahash_request_ctx(req);
+
+	if (!req->nbytes)
+		return 0;
+
+	dev_dbg(ctx->crc->dev, "crc_update\n");
+	ctx->total += req->nbytes;
+	ctx->flag = CRC_CRYPTO_STATE_UPDATE;
+
+	return bfin_crypto_crc_handle_queue(ctx->crc, req);
+}
+
+static int bfin_crypto_crc_final(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct bfin_crypto_crc_ctx *crc_ctx = crypto_ahash_ctx(tfm);
+	struct bfin_crypto_crc_reqctx *ctx = ahash_request_ctx(req);
+
+	dev_dbg(ctx->crc->dev, "crc_final\n");
+	ctx->flag = CRC_CRYPTO_STATE_FINISH;
+	crc_ctx->key = 0;
+
+	return bfin_crypto_crc_handle_queue(ctx->crc, req);
+}
+
+static int bfin_crypto_crc_finup(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct bfin_crypto_crc_ctx *crc_ctx = crypto_ahash_ctx(tfm);
+	struct bfin_crypto_crc_reqctx *ctx = ahash_request_ctx(req);
+
+	dev_dbg(ctx->crc->dev, "crc_finishupdate\n");
+	ctx->total += req->nbytes;
+	ctx->flag = CRC_CRYPTO_STATE_FINALUPDATE;
+	crc_ctx->key = 0;
+
+	return bfin_crypto_crc_handle_queue(ctx->crc, req);
+}
+
+static int bfin_crypto_crc_digest(struct ahash_request *req)
+{
+	int ret;
+
+	ret = bfin_crypto_crc_init(req);
+	if (ret)
+		return ret;
+
+	return bfin_crypto_crc_finup(req);
+}
+
+static int bfin_crypto_crc_setkey(struct crypto_ahash *tfm, const u8 *key,
+			unsigned int keylen)
+{
+	struct bfin_crypto_crc_ctx *crc_ctx = crypto_ahash_ctx(tfm);
+
+	dev_dbg(crc_ctx->crc->dev, "crc_setkey\n");
+	if (keylen != CHKSUM_DIGEST_SIZE) {
+		crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return -EINVAL;
+	}
+
+	crc_ctx->key = get_unaligned_le32(key);
+
+	return 0;
+}
+
+static int bfin_crypto_crc_cra_init(struct crypto_tfm *tfm)
+{
+	struct bfin_crypto_crc_ctx *crc_ctx = crypto_tfm_ctx(tfm);
+
+	crc_ctx->key = 0;
+	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
+				 sizeof(struct bfin_crypto_crc_reqctx));
+
+	return 0;
+}
+
+static void bfin_crypto_crc_cra_exit(struct crypto_tfm *tfm)
+{
+}
+
+static struct ahash_alg algs = {
+	.init		= bfin_crypto_crc_init,
+	.update		= bfin_crypto_crc_update,
+	.final		= bfin_crypto_crc_final,
+	.finup		= bfin_crypto_crc_finup,
+	.digest		= bfin_crypto_crc_digest,
+	.setkey		= bfin_crypto_crc_setkey,
+	.halg.digestsize	= CHKSUM_DIGEST_SIZE,
+	.halg.base	= {
+		.cra_name		= "hmac(crc32)",
+		.cra_driver_name	= DRIVER_NAME,
+		.cra_priority		= 100,
+		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
+						CRYPTO_ALG_ASYNC,
+		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct bfin_crypto_crc_ctx),
+		.cra_alignmask		= 3,
+		.cra_module		= THIS_MODULE,
+		.cra_init		= bfin_crypto_crc_cra_init,
+		.cra_exit		= bfin_crypto_crc_cra_exit,
+	}
+};
+
+static void bfin_crypto_crc_done_task(unsigned long data)
+{
+	struct bfin_crypto_crc *crc = (struct bfin_crypto_crc *)data;
+
+	bfin_crypto_crc_handle_queue(crc, NULL);
+}
+
+static irqreturn_t bfin_crypto_crc_handler(int irq, void *dev_id)
+{
+	struct bfin_crypto_crc *crc = dev_id;
+
+	if (crc->regs->status & DCNTEXP) {
+		crc->regs->status = DCNTEXP;
+		SSYNC();
+
+		/* prepare results */
+		put_unaligned_le32(crc->regs->result, crc->req->result);
+
+		crc->regs->control &= ~BLKEN;
+		crc->busy = 0;
+
+		if (crc->req->base.complete)
+			crc->req->base.complete(&crc->req->base, 0);
+
+		tasklet_schedule(&crc->done_task);
+
+		return IRQ_HANDLED;
+	} else
+		return IRQ_NONE;
+}
+
+#ifdef CONFIG_PM
+/**
+ *	bfin_crypto_crc_suspend - suspend crc device
+ *	@pdev: device being suspended
+ *	@state: requested suspend state
+ */
+static int bfin_crypto_crc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct bfin_crypto_crc *crc = platform_get_drvdata(pdev);
+	int i = 100000;
+
+	while ((crc->regs->control & BLKEN) && --i)
+		cpu_relax();
+
+	if (i == 0)
+		return -EBUSY;
+
+	return 0;
+}
+#else
+# define bfin_crypto_crc_suspend NULL
+#endif
+
+#define bfin_crypto_crc_resume NULL
+
+/**
+ *	bfin_crypto_crc_probe - Initialize module
+ *
+ */
+static int __devinit bfin_crypto_crc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct bfin_crypto_crc *crc;
+	unsigned int timeout = 100000;
+	int ret;
+
+	crc = kzalloc(sizeof(*crc), GFP_KERNEL);
+	if (!crc) {
+		dev_err(&pdev->dev, "fail to malloc bfin_crypto_crc\n");
+		return -ENOMEM;
+	}
+
+	crc->dev = dev;
+
+	INIT_LIST_HEAD(&crc->list);
+	spin_lock_init(&crc->lock);
+	tasklet_init(&crc->done_task, bfin_crypto_crc_done_task, (unsigned long)crc);
+	crypto_init_queue(&crc->queue, CRC_CCRYPTO_QUEUE_LENGTH);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL) {
+		dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
+		ret = -ENOENT;
+		goto out_error_free_mem;
+	}
+
+	crc->regs = ioremap(res->start, resource_size(res));
+	if (!crc->regs) {
+		dev_err(&pdev->dev, "Cannot map CRC IO\n");
+		ret = -ENXIO;
+		goto out_error_free_mem;
+	}
+
+	crc->irq = platform_get_irq(pdev, 0);
+	if (crc->irq < 0) {
+		dev_err(&pdev->dev, "No CRC DCNTEXP IRQ specified\n");
+		ret = -ENOENT;
+		goto out_error_unmap;
+	}
+
+	ret = request_irq(crc->irq, bfin_crypto_crc_handler, IRQF_SHARED, dev_name(dev), crc);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to request blackfin crc irq\n");
+		goto out_error_unmap;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+	if (res == NULL) {
+		dev_err(&pdev->dev, "No CRC DMA channel specified\n");
+		ret = -ENOENT;
+		goto out_error_irq;
+	}
+	crc->dma_ch = res->start;
+
+	ret = request_dma(crc->dma_ch, dev_name(dev));
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to attach Blackfin CRC DMA channel\n");
+		goto out_error_irq;
+	}
+
+	crc->sg_cpu = dma_alloc_coherent(&pdev->dev, PAGE_SIZE, &crc->sg_dma, GFP_KERNEL);
+	if (crc->sg_cpu == NULL) {
+		ret = -ENOMEM;
+		goto out_error_dma;
+	}
+	/*
+	 * need at most CRC_MAX_DMA_DESC sg + CRC_MAX_DMA_DESC middle  +
+	 * 1 last + 1 next dma descriptors
+	 */
+	crc->sg_mid_buf = (u8 *)(crc->sg_cpu + ((CRC_MAX_DMA_DESC + 1) << 1));
+
+	crc->regs->control = 0;
+	SSYNC();
+	crc->regs->poly = crc->poly = (u32)pdev->dev.platform_data;
+	SSYNC();
+
+	while (!(crc->regs->status & LUTDONE) && (--timeout) > 0)
+		cpu_relax();
+
+	if (timeout == 0)
+		dev_info(&pdev->dev, "init crc poly timeout\n");
+
+	spin_lock(&crc_list.lock);
+	list_add(&crc->list, &crc_list.dev_list);
+	spin_unlock(&crc_list.lock);
+
+	platform_set_drvdata(pdev, crc);
+
+	ret = crypto_register_ahash(&algs);
+	if (ret) {
+		spin_lock(&crc_list.lock);
+		list_del(&crc->list);
+		spin_unlock(&crc_list.lock);
+		dev_err(&pdev->dev, "Cann't register crypto ahash device\n");
+		goto out_error_dma;
+	}
+
+	dev_info(&pdev->dev, "initialized\n");
+
+	return 0;
+
+out_error_dma:
+	if (crc->sg_cpu)
+		dma_free_coherent(&pdev->dev, PAGE_SIZE, crc->sg_cpu, crc->sg_dma);
+	free_dma(crc->dma_ch);
+out_error_irq:
+	free_irq(crc->irq, crc->dev);
+out_error_unmap:
+	iounmap((void *)crc->regs);
+out_error_free_mem:
+	kfree(crc);
+
+	return ret;
+}
+
+/**
+ *	bfin_crypto_crc_remove - Initialize module
+ *
+ */
+static int __devexit bfin_crypto_crc_remove(struct platform_device *pdev)
+{
+	struct bfin_crypto_crc *crc = platform_get_drvdata(pdev);
+
+	if (!crc)
+		return -ENODEV;
+
+	spin_lock(&crc_list.lock);
+	list_del(&crc->list);
+	spin_unlock(&crc_list.lock);
+
+	crypto_unregister_ahash(&algs);
+	tasklet_kill(&crc->done_task);
+	iounmap((void *)crc->regs);
+	free_dma(crc->dma_ch);
+	if (crc->irq > 0)
+		free_irq(crc->irq, crc->dev);
+	kfree(crc);
+
+	return 0;
+}
+
+static struct platform_driver bfin_crypto_crc_driver = {
+	.probe     = bfin_crypto_crc_probe,
+	.remove    = __devexit_p(bfin_crypto_crc_remove),
+	.suspend   = bfin_crypto_crc_suspend,
+	.resume    = bfin_crypto_crc_resume,
+	.driver    = {
+		.name  = DRIVER_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+
+/**
+ *	bfin_crypto_crc_mod_init - Initialize module
+ *
+ *	Checks the module params and registers the platform driver.
+ *	Real work is in the platform probe function.
+ */
+static int __init bfin_crypto_crc_mod_init(void)
+{
+	int ret;
+
+	pr_info("Blackfin hardware CRC crypto driver\n");
+
+	INIT_LIST_HEAD(&crc_list.dev_list);
+	spin_lock_init(&crc_list.lock);
+
+	ret = platform_driver_register(&bfin_crypto_crc_driver);
+	if (ret) {
+		pr_info(KERN_ERR "unable to register driver\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ *	bfin_crypto_crc_mod_exit - Deinitialize module
+ */
+static void __exit bfin_crypto_crc_mod_exit(void)
+{
+	platform_driver_unregister(&bfin_crypto_crc_driver);
+}
+
+module_init(bfin_crypto_crc_mod_init);
+module_exit(bfin_crypto_crc_mod_exit);
+
+MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
+MODULE_DESCRIPTION("Blackfin CRC hardware crypto driver");
+MODULE_LICENSE("GPL");